Brussels, 18-20 February 2008 Dissemination of information workshop 1 Conceptual design and design examples for multi-storey buildings Dr.-Ing. Christian Müller Dipl.-Ing. Matthias Oppe RWTH Aachen
Overview Brussels, 18-20 February 2008 Dissemination of information workshop 2 Client Guide Case Studies Scheme Development Flow Charts NCCI Examples Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 3 Client briefing: guides, case studies and concept designs demonstrate the value that steel offers for economic, fast, adaptable, safe, construction 1. Introduction Commercial buildings, such as offices, shops and mixed residential-commercial buildings, account for 20% of construction output in the EU, representing over 20 million square metres of floor space per year. The commercial sector demands buildings that are rapid to construct, of high quality, flexible and adaptable in application, and energy efficient in use. Steel and composite construction has achieved over 60% market share in this sector in some countries of Europe where the benefits of long spans, speed of construction, improved quality and reduced environmental impact have been recognised. A wide range of steel technologies may be used in commercial buildings. Specific technologies are chosen to match client requirements. Many long span steel solutions provide service integration within their depth, which saves on building height. Cellular beams combine an efficient manufacturing process with opportunities for service integration. Integrated beams minimise the floor zone while allowing services uninterrupted access below the floor soffit. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 4 2. Maximum Value from Steel Construction Speed of Construction Flexibility and adaptability Service integration Reduced disruption to the locality Quality Safer Construction Environmental Benefits Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 5 3. Construction Systems and their Ranges of Application Span range Structure depth 800 mm 6 to 15 m 400 to Composite construction using steel decking Cellular beams in composite construction Span range 9 to 18 m Structure depth 600 to 1000 mm Span range 9 to 20 m Structure depth 600 to 1200 mm Fabricated or rolled beams with large web openings Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 6 Integrated beams with deep decking Span range 5 to 9 m Structure depth 300 to 350 mm Integrated beams supporting precast concrete slabs Span range 5 to 9 m Structure depth 300 to 400 mm Span range 5 to 10 m Structure depth 500 to 900 mm Steel beams supporting precast concrete slabs Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 7 4. Specific Technologies for Commercial Buildings Commercial buildings require a range of specific technologies that have been developed to meet client needs: Service Integration: Cellular beams with regular openings for services Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 8 Service integration in integrated beams Fabricated beams with variety of shapes of openings Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 9 Fire Resistance Tubular columns exposed for fire resistance Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 10 Energy Efficiency Energy efficient design at GLA building, London Double façade in the Kone Building, Finland Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Client Guide Brussels, 18-20 February 2008 Dissemination of information workshop 11 Cladding and infill walls large variety of cladding systems: traditional brickwork, curtain walling and glazing Light steel infill walls as sub-structure to all types of facades Double skin glazed façades to reduce solar gain Light steel infill walls used in steel framed buildings Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Case Studies Brussels, 18-20 February 2008 Dissemination of information workshop 12 Access Steel highlights the benefits of steel as the primary construction material through detailed short case studies of successful buildings Le Sequana, Paris Kista Science Tower, Stockholm Place d'lena, Paris Office Building, Palestra, London Luxembourg Chamber of Commerce's ING Headquarters, Amsterdam Sheraton Hotel, Bilbao Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Le Sequana, Paris Brussels, 18-20 February 2008 Dissemination of information workshop 13 near completation Le Sequana artist s impression 25,000 m² of exceptional quality office accommodation in the heart of the new commercial centre, Ville de Paris Column free spaces of 18 m x 36 m overlooking the Seine 33% pre-let from plan, prior to the commencement of construction Fully air conditioned with individual control for every 12m² Construction completed in 22 months to programme and budget, including the erection of 2000 tonnes of structural steelwork in 12 weeks Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Kista Science Tower, Stockholm Brussels, 18-20 February 2008 Dissemination of information workshop 14 Kista Science Tower: 42000 m 2 of high quality office space in six buildings, 158 meters tall with 32 storeys. Long span steel trusses create open space overlooking northern Stockholm. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Place d Ilena, Paris Brussels, 18-20 February 2008 Dissemination of information workshop 15 Completed building showing the new façade Demolition stage of the original concrete frame Refurbishment of a building constructed in the 1960 s to create large open spaces for a high quality office building in one of the most prestigious districts in Paris The project involved preservation of the existing façades of the building, which imposed a constraint on the method of building Creation of office open spaces of 1200 m² without intermediate columns Floor span of up to 14 m Service integration in cellular beams achieves minimum floor zone Construction completed in 22 months Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Office Building Palestra, London Brussels, 18-20 February 2008 Dissemination of information workshop 16 During construction, showing steel framework and fully glazed facade 12 storey building of 31,5 to 36 m width and 90 m length with a 9 m projection of the upper 4 floors Pairs of cellular beams were placed either side of the 4 inclined tubular columns. The cellular beams were designed as continuous over a span of 15 m in order to reduce their depth The floor-floor zone is a minimum of 3,65 m and the structure and services zone is only 850 mm. The cellular beams permit passage of 400 mm diameter circular service ducts Fully glazed façade, which was directly attached to the composite slab The inclined tubular columns and shear connections were designed for an eccentric load transfer which carried bending in the columns. The columns used innovative double circular hollow sections filled with cement grout to achieve 120 minutes fire resistance Erection of the 3500 tonnes of steelwork in only 10 months Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Luxembourg Chamber of Commerce s Brussels, 18-20 February 2008 Dissemination of information workshop 17 Chamber of Commerce s 20 000 m 2 of new 5 storey office space, a conference centre of 8 000 m² and 650 underground car parking spaces on 4 below ground levels. Full double-glazed ventilated façade with shading with serigraphed glass shields. Water-cooled composite slab using sinusoidal stainless steel façade, which acted as framework to the concrete slab of 300 mm depth. No temporary propping was required. Integrated IFB beams with under-tied hollow sections to create a span of 12,5 m, which is 30% larger than is possible with integrated beams. These beams are exposed usually. Fire engineering, using natural fire approach, led to a fully unprotected steel structure. These operating conditions for the water-cooled slab are: Summer-night-time; Summer-day-time and winter. Heating and cooling is provided Diaphragm action of composite slab and stability through the lift shaft. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
ING Headquaters, Amsterdam Brussels, 18-20 February 2008 Dissemination of information workshop 18 9 storey steel structure of 20 000 m 2 floor area supported on inclined columns. The 'nose' of the building provides an auditorium and cantilevers 26 m from the adjoining structure. A shallow construction depth of 310 mm was achieved using Slimdek for a structural grid of approximately 7 m. Slimdek consists of asymmetric steel beams (ASB) support a deep composite slab. The inclined columns support the entire weight of the building and provide overall stability. They are designed as composite sections. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
ING Headquaters, Amsterdam Brussels, 18-20 February 2008 Dissemination of information workshop 19 Composite floor slab in the auditorium area showing service penetrations The space between the inclined legs provides access to the building and to the below-ground car parking. A double skin glass façade was used to control 'solar gain' and regulate internal temperatures. Minimum ground works were required by concentrating loads at discrete points. A fire resistance of 90 minutes was satisfied by a fire engineering analysis. Slimdek minimised the visual impact of the structure, which was important for the architectural concept. Steelwork was supplied by a consortium of 3 fabricators. Erection of the 1 000 tonnes of steelwork took only 28 weeks. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Sheraton Hotel, Bilbao Brussels, 18-20 February 2008 Dissemination of information workshop 20 20 000 m² multi-storey luxury hotel in Bilbao: 11 above-ground storeys of 13 000 m² floor area: and 4 below ground floors of 7 000 m² floor area. 211 rooms: one presidential suite, 20 suites and 190 double rooms. 1 100 tonnes of structural steelwork were used in the form of I and H sections, tubes and plates. Only 7 months for the erection of the steel structure. The Sheraton hotel has a high level of building services comprising: Full air conditioning system in all rooms and in common areas, and radiant flooring in the atrium. Architectural design for optimised energy requirements, such as natural cooling, solar gains or natural daylight. Emergency electric power plant for essential facilities, such as the fire protection, safety and UPS-supported computer network installations. Optical fibre voice and data networks to all rooms. Fire detection and extinguishing network, backed up by a computerized management system that enables the fire to be located immediately. Advanced Smoke Control systems and safe means of egress in fire. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 21 Form and function Key information Location and its influence on the design of MSB Service strategies Overview Service buildings Sustainability Overview Sustainability factors Fire Safety Structural System Composite Slabs, Web Openings etc. Vertical Structure 16 documents Concise information on proposal development guides the architect and engineer through all the decisions that have to be made to develop a best practice design Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 22 Coordination of structural and architectural design for multi-storey buildings with steel frames Floor Grids Influence of Building Height Horizontal Coordination Vertical Coordination: Floor-to-Floor Heights Vertical Coordination: Structural Zone Vertical Coordination: Service Zones Horizontal Structural Options Span Range of Structural Systems Benefits of Long Span Construction Approximate Steel Quantities Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 23 Floor Grids Influenced by: Planning Grid Column Spacing Use of internal space Requirements of Building Service Integration Column grid for long span floor in a prestige air-conditioned office Column grid for a naturally ventilated office Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 24 Building Height The building height has a strong influence on the: Structural system that is adopted. Foundation system. Fire resistance requirements and means of escape. Access (by lifts) and circulation space. Cladding system. Speed of construction and site productivity. The structural system is primarily influenced by the means of stabilizing the building. For buildings up to 8 storeys high, vertical bracing is preferred, but for taller buildings, strategically placed concrete or braced steel cores are usually adopted. For ultra-tall buildings, many types of external bracing systems have been used. These are outside the scope of this information. Sizes of lifts and their speed of movement also become important considerations for tall buildings. Depending on the Regulations for fire safety in the particular country, the use of sprinklers may be required or buildings of more than 8 storeys. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 25 Horizontal coordination / Position of cores Positioning of cores is influenced by: Horizontal distribution systems for mechanical services. Fire rating requirements, which may lead to shortened evacuation routes, and to reduced compartment sizes. The need to distribute the structural stabilizing systems more-or-less symmetrically throughout the building plan. Beam layout around a concrete core Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 26 Vertical coordination / Floor-to-Floor Heights Prestige office 3,8 4,2 m Speculative office 3,5 4,0 m Renovation project 3,5 3,9 m Vertical coordination / Structural Zone Composite beams Span/depth ratio 25 Cellular beams Span/depth ratio 25 Fabricated primary beams Span/depth ratio 20 Slim floor or integrated beams Span/depth ratio 25 Vertical coordination / Service Zones Raised access floor 150 to 200 mm Air-conditioning units 400 to 500 mm Ceiling and lighting 120 to 250 mm Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 27 Horizontal Structural Options Composite beams (with composite slabs) Non-composite beams (with precast planks) Partially encased composite beams Cellular or fabricated beams (with composite slabs) Slim floor or integrated beams Spans of 6 to 13 m Spans of 6 to 9 m Spans of 6 to 12 m Spans of 8 to 18 m Spans of 5 to 9 m Forms of construction used in floors 1. Composite beam 2. Partially encased beam 3. Integrated beam 4. Slim floor beam Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 28 Horizontal Structural Options Typical long span secondary beams Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 29 Horizontal Structural Options Typical long span primary beams and shorter span secondary beams Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 30 Horizontal Structural Options Integrated beams or slim floor Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 31 Span Range of various structural systems Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 32 Benefits of Long Span Construction Long span beams have gained in popularity in the commercial building sector because they offer the following benefits in design and construction: Internal columns are eliminated, leading to more flexible and efficient use of internal space. Services can be integrated within the depth of the structure, and so the floor-to-floor depth is not increased. Fewer components are required (typically 30% fewer beams) leading to reduced construction and installation time. Fire protection costs can be reduced due to the massivity of the longer span members. For cellular beams, multiple circular ducts for services are cheaper than rectangular ducts. Steelwork costs are not increased significantly, despite the longer spans. Overall building costs are increased by a negligible amount (less than 1%). Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Scheme Development Brussels, 18-20 February 2008 Dissemination of information workshop 33 Approximate Steel Quantities Form of Building Approximate steel quantities (kg/m 2 floor area) Beams Columns Bracing Total 3 or 4 storey building of rectangular form 25 30 8 10 2 3 35 40 6 8 storey building of rectangular form 25 30 12 15 3 5 40 50 8 10 storey building with long spans 35 40 12 15 3 5 50 60 20 storey building with a concrete core 40 50 10 13 1 2 55 65 20 storey building with a braced steel core 40 50 20 25 8 10 70 85 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 34 Evaluation of wind loads Governing load combinations Frame Analysis Choosing a steel sub-grade Column design Non composite beams / Composite Beams Design of vertical bracings Simple Connections Secondary beam design 21 documents Each design activity is described separately by a flow chart: Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 35 Evaluation of wind loads Governing load combinations Frame Analysis Choosing a steel sub-grade Column design Non composite beams / Composite Beams Design of vertical bracings Simple Connections Secondary beam design 21 documents Each design activity is described separately by a flow chart: Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 36 Choosing a steel subgrade Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 37 Choosing a steel subgrade Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 38 Column design Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 39 Column design Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 40 Column design Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 41 Column design Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 42 Column design Determination of interaction criteria for both axes Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Flow Charts Brussels, 18-20 February 2008 Dissemination of information workshop 43 Column design Determination of interaction criteria for both axes Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
NCCI Brussels, 18-20 February 2008 Dissemination of information workshop 44 34 documents Non-contradictory, complementary information (NCCI) is presented that addresses all the information that the Eurocodes do not cover that is essential for design, e.g.: Calculation of α crit Vertical and horizontal deflection limits Effective lengths of columns Torsional Buckling (calculation of N cr,t and M cr,t ) Design Rules for Web Openings in Beams Torsion (Section Properties and stresses) Vibrations Sizing Guidance Horizontal and vertical Bracings Design Model for simple Column Splices Choice of Method for Frame Analysis Simplified Bracing Systems Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
NCCI Brussels, 18-20 February 2008 Dissemination of information workshop 45 34 documents Non-contradictory, complementary information (NCCI) is presented that addresses all the information that the Eurocodes do not cover that is essential for design Calculation of α crit Vertical and horizontal deflection limits Effective lengths of columns Torsional Buckling (calculation of N cr,t and M cr,t ) Design Rules for Web Openings in Beams Torsion (Section Properties and stresses) Vibrations Sizing Guidance Horizontal and vertical Bracings Design Model for simple Column Splices Choice of Method for Frame Analysis Simplified Bracing Systems Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
NCCI Brussels, 18-20 February 2008 Dissemination of information workshop 46 Calculation of α cr This NCCI sets out the basis for the calculation of α cr, the parameter that measures the stability of the frame. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 47 Calculation of α cr Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 48 Calculation of α cr Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 49 Calculation of α cr Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
NCCI Brussels, 18-20 February 2008 Dissemination of information workshop 50 Effective lengths of columns This NCCI gives information concerning the calculation of the buckling length for columns, to be used for the buckling verification (slenderness approach). Simple aids (e.g. tables, diagrams) are presented. Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 51 Effective lengths of columns Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 52 Effective lengths of columns Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 53 Effective lengths of columns Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 54 Effective lengths of columns Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 55 Effective lengths of columns Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 56 Effective lengths of columns Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Examples Brussels, 18-20 February 2008 Dissemination of information workshop 57 13 documents Calculation of α crit Choosing a steel sub-grade Simply supported secondary composite beams Simply supported primary composite beams Simply supported beam with lateral restraint at load Pinned column with intermediate restraint Sway stability Tying and avoidance of disproportionate collapse Beam to beam fin plate connection Beam to column end plate connection Column splice (Non-Bearing / Bearing) Column base, axially loaded Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Examples Brussels, 18-20 February 2008 Dissemination of information workshop 58 13 documents Calculation of α crit Choosing a steel sub-grade Simply supported secondary composite beams Simply supported primary composite beams Simply supported beam with lateral restraint at load Pinned column with intermediate restraint Sway stability Tying and avoidance of disproportionate collapse Beam to beam fin plate connection Beam to column end plate connection Column splice (Non-Bearing / Bearing) Column base, axially loaded Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Choosing a steel sub-grade Brussels, 18-20 February 2008 Dissemination of information workshop 59 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Choosing a steel sub-grade Brussels, 18-20 February 2008 Dissemination of information workshop 60 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Choosing a steel sub-grade Brussels, 18-20 February 2008 Dissemination of information workshop 61 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Choosing a steel sub-grade Brussels, 18-20 February 2008 Dissemination of information workshop 62 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Choosing a steel sub-grade Brussels, 18-20 February 2008 Dissemination of information workshop 63 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Choosing a steel sub-grade Brussels, 18-20 February 2008 Dissemination of information workshop 64 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Buckling resistance Brussels, 18-20 February 2008 Dissemination of information workshop 65 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Buckling resistance Brussels, 18-20 February 2008 Dissemination of information workshop 66 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Buckling resistance Brussels, 18-20 February 2008 Dissemination of information workshop 67 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Buckling resistance Brussels, 18-20 February 2008 Dissemination of information workshop 68 Overview Client Guide Case Studies Scheme Development Flow Charts NCCI Examples
Brussels, 18-20 February 2008 Dissemination of information workshop 69 Conceptual design and design examples for multi-storey buildings Dr.-Ing. Christian Müller Dipl.-Ing. Matthias Oppe RWTH Aachen